NAME
Math::Erf::Approx - pure Perl approximate implementation of the error
function
DESCRIPTION
This is a pure Perl implementation of the error function (a.k.a. the Gauss
error function). It gives an approximation with a maximum absolute
difference of 0.0005 from the real value.
Functions
This module can export two functions. Neither is exported by default. This
module uses Sub::Exporter, so the functions can be renamed:
use Math::Erf::Approx -all => { -prefix => 'math_' };
`erf($x)`
Calculates the result of the error function for value $x.
`erfc($x, \&erf)`
Given a value $x and a code reference to an implementation of erf(),
calculates the complement.
If the code reference is ommitted (which I'd expect would be the most
usual case), then the default is the `erf` function provided by this
module.
Testing
It is possible to run a small test suite on this module using:
use Math::Erf::Approx;
Math::Erf::Approx->run_tests;
BENCHMARKS
Benchmarking against Games::Go::Erf (on a fairly underpowered netbook)...
Benchmark: timing 100000 iterations of GGE, MEA...
GGE: 6 wallclock secs ( 6.34 usr + 0.01 sys = 6.35 CPU) @ 15748.03/s (n=100000)
MEA: 3 wallclock secs ( 2.71 usr + 0.00 sys = 2.71 CPU) @ 36900.37/s (n=100000)
There are considerations other than raw speed though...
* Games::Go::Erf provides much more accurate results
* ... and it can calculate inverses
* ... but it has a dependency on Tk
* ... and it sets $[ to 1, which has been deprecated since Perl 5.12.
SEE ALSO
.
*Handbook of Mathematical Functions with Formulas, Graphs, and
Mathematical Tables*, ed Milton Abramowitz and Irene Stegun. ISBN
0-486-61272-4.
AUTHOR
Toby Inkster .
COPYRIGHT AND LICENCE
This software is copyright (c) 2012 by Toby Inkster.
This is free software; you can redistribute it and/or modify it under the
same terms as the Perl 5 programming language system itself.
DISCLAIMER OF WARRANTIES
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.